1. Field of the Invention
The present invention relates to an yttrium aluminum garnet phosphor material, a method of preparing the same and a light-emitting diode device containing the same, more particularly, to a silicon-doped yttrium aluminum garnet phosphor material, a method of preparing the same and a light-emitting diode device containing the same.
2. Description of Related Art
Owing to energy shortage, climate warming and the rise in eco-awareness, green technologies have become one of the main development aims in the technology related to energy conservation. In particular, many advanced countries in the world have been actively involved in the development of white LEDs to replace traditional lighting equipments in recent years.
Compared to traditional incandescent lamps and fluorescent lamps, LEDs have the advantages of compact volume, low heat radiation, low power consumption, long lifetime, rapid response and environmentally friendliness, and can be flat-packaged for the development of light, thin and small products. Therefore, LEDs can be considered as a potential for new light sources for 21th century in the lighting file due to their properties of electricity saving and environmental protection.
In a traditional LED package, phosphor powder is mixed with a polymer resin or epoxy and then coated on a LED chip. As shown in FIG. 1, a conventional LED device includes an LED chip 101 and an encapsulating material 102 that includes phosphor powder 103 dispersed therein and covers the light output surface of the LED chip 101.
However, such package structure often suffers from poor thermal dissipation and is particularly unsuitable for high performance LED devices that require high thermal performance. Besides, the yellowing of the polymer resin used for the encapsulating material 102 may occur under long-term high temperature circumstance, and thus adversely affects luminous efficiency of LEDs and greatly shortens the lifetime of LEDs.
Therefore, it is desirable to develop a novel phosphor material that can exhibit high photoelectric conversion efficiency and can be applied in LED package structures other than the existing LED package to mitigate the problems induced by the yellowing of the encapsulating material.